Cam switching mechanism for motor control system



Nov. 2, 1965 W.'HCLZER 3,215,919

CAM SWITCHING MECHANiSM FOR MOTOR CONTROL SYSTEM Filed Jul 18. 1960 MANUAL 0/? PROGRAM FIG.I.

FIG.2.

N VE N 7' OR WALTER HOLZER A Horneys United States Patent 3,215,919 CAM SWITCHING MECHANISM FOR MOTOR CONTROL SYSTEM Walter Holzer, 19 Drosteweg, Meersburg (Bodensee), Germany Filed July 18, 1960, Ser. No. 43,560 Claims priority, application Germany, July 25, 1959, H 37,019 3 Claims. (Cl, 318349) The present invention relates to a control device for automatic washing machines having program switching mechanisms.

Programme switching mechanisms are known which permit the provision of different operating speeds of actuating the contact system. In particular, systems are known with one or more motors which drive a stepping mechanism, and according to the selection of various driving speeds, the speed of the switching action of the contact system is altered.

These systems have, however, the disadvantage that mostly owing to expense only two speeds are provided, namely an ordinary working speed of e.g. one step per minute and a rapid working speed for several steps per second to pass over or to shorten the duration of any individual programme section.

It is an object of the present invention to provide a new step switching device capable of operating at any number of operating speeds.

It is another object of the present invention to provide an improvement in control devices for automatic washing machines.

In accordance with the invention it is to proposed to combine a stepping mechanism with an auxiliary contact system which, after partial completion of a step, changes the speed of the motor driving the stepping mechanism. Thus, for example, after only half the normal time for completion of a step has elapsed the auxiliary contact system switches over to a rapid drive, whereby the programme switch mechanism at once enters the next stepping position.

A further feature of the invention is that the auxiliary contact system returns the drive to the original speed after completion of the switch step; i.e. after completion of a shortened step the drive continues to drive the stepping switch mechanism at its normal speed.

It is possible for several auxiliary contacts to be present which are actuated successively. It is thus possible to use the rapid gear for selectively shortening the switch steps.

It is particularly expedient for the auxiliary contacts to be switched on either by hand or by programme contacts during the programme sequence.

In this way a shortening of the process can be obtained either by hand at a manual program selection or during the run of a program. Especially by switching over of the auxiliary contacts by programme contacts on switch mechanism it is possible to alter the timing of whole series of processes. In particular, the embodiment of the programme switch mechanism contained in the invention makes it possible to increase the length of step for long programme times considerably, e.g. to 3 minutes or even longer and despite this it is possible to carry out short steps and processes selectively by use of the auxiliary contacts. In the accompanying drawings the invention is explained more fully and they contain further features thereof.

FIG. 1 is a schematic circuit diagram showing several mechanical elements to be employed in side view and thus illustrates the cooperation thereof with the circuit network, and

3,215,919 Patented Nov. 2, 1965 ice FIG. 2 illustrates way-time diagrams of a step switching device operated in accordance with the invention.

In FIG. 1 there is a switch mechanism including a cam 1 raising a pivotable lever 2 against the force of a tension spring 3. Lever 2 has a pawl 2a engaging the teeth of a ratchet wheel 11 for step switching the program switching mechanism 15 by one step for each turn of the cam 1. The step switching mechanism is driven from ratchet Wheel 11 via a shaft 4. The program contact system is only diagrammatically represented. Cam 1 is driven by a motor 12 connected to a voltage source via series resistors 13, 14 constituting a control circuit for the motor; the resistors may be short-circuited by auxiliary contacts 7, 5, 6. As was said above, auxiliary contacts may be switched on either manually or by the program control.

Likewise, in place of the step switching mechanism, any other system can be used which converts the continuous drive motion of the motor into a stepped motion of the programme contact system.

In FIG. 1 the auxiliary contact system is indicated by 5 and 6. When the cam 1 is turned, contact 7 will (after a partial turn) first engage contact 5 and thereafter contact 6. These contacts are now used to convert the drive of the cam 1 to higher speed by short circuiting resistors 13 and 14 and the cam then rapidly completes its rotary movement, whereby the period of time for completion of the step is reduced. If, however, a lesser reduction of the step is desired, one may selectively use only the contact 5 which bridges the resistor 13 for the switch-over of the drive speed. It is characteristic of the invention that after the completion of the switch step all the auxiliary contacts are re-opened because lever 2 drops at edge 1 of cam 1. Thus, motor 12 and cam 1 regain their original turning speed.

FIG. 2 is a motion diagram of the stepping mechanism according to FIG. 1. The up and down movements of the pawl 2a normally together take the same length of time 8. The lower diagram in FIG. 2 shows in the second and third step a first reduction of duration for such steps. At the spot marked 10 the contacts 5 and 7 close, thus bridging resistor 13 and the motor 12 drives the cam at a higher speed than before. This causes a reduction of the normal step of length 8 to the reduced length of step 9.

In the following step it is assumed that also contact 6 becomes efiective electrically so that at 10a there is a first increase in motor speed, while at 10b the speed is still further increased, reducing the stepping time to a period indicated with 9.

For the execution of the invention idea the type of auxiliary connection is unimportant. It can be developed in the manner represented or it can be a sliding contact system or an arrangement of several key contacts otfset at the particular turning angle.

It is also unimportant what kind of speed switch-over is used. The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be covered by the following claims:

1. In a control device for automatic washing machines having steps operating at variable duration, the combination comprising a rotatable means, an electric motor drivingly connected to said means, a plurality of resistors connected in series with said motor and electric contacts selectively bridging said resistors, said means closing said contacts successively after completion of a portion of a step and opening the contacts upon completion of a step; means operated by said first means, stepwise driving a shaft upon completion of a step.

2. The invention as defined in claim 1, wherein manual means are employed for controlling the effectiveness of at leasLone other of said bridges.

3. In a control device for automatic washing machines having variable stepping speeds, the combination compris-v ing a rotatable cam, an electric motor drivingly connected to said cam, a resistor connected in series with said motor, and electric contacts bridging said resistor, said cam closing said contacts and thereby increasing the speed of rotation of the motor and completion of a portion of a step, said cam opening the contacts upon completion of a step, means operated by said cam, stepwise driving a shaft also upon completion of a step.

References Cited by the Examiner UNITED STATES PATENTS 2,060,437 11/36 Harley 3l8164 2,627,593 2/53 Tietig 318-164 2,798,195 7/57 Lembo 318-296 X FOREIGN PATENTS 478,124 1/3 8 Great Britain.

ORIS L. RADER, Primary Examiner.

MAX L. LEVY, Examiner. 

1. IN A CONTROL DEVICE FOR AUTOMATIC WASHING MACHINES HAVING STEPS OPERATING AT VARIABLE DURATION, THE COMBINATION COMPRISING A ROTATABLE MEANS, AND ELECTRIC MOTOR DRIVINGLY CONNECTED TO SAID MEANS, A PLURALITY OF RESISTORS CONNECTED IN SERIES WITH SAID MOTOR AND ELECTRIC CONTACTS SELECTIVE BRIDGING SAID RESISTORS, SAID MEANS CLOSING SAID CONTACTS SUCCESSIVELY AFTER COMPLETION OF A PORTION OF A STEP AND OPENING THE CONTACTS UPON COMPLETION OF A STEP; MEANS OPERATED BY SAID FIRST MEANS, STEPWISE DRIVING A SHAFT UPON COMPLETION OF A STEP. 